Single-door small 120V fridge under 5 cf... No real freezer, tiny freezer tray that (barely) keeps it below freezing. As said, you need a good solar for this, at least 200W. In winter even in the South you might need 300-400W. About $400-500 for solar parts, depending on size. And a pair of good batteries. If your current problem is too much pain already, I would guess that installing solar yourself is not an option, you'll have to pay somebody BIG TIME.
Near-full-size residential 120V... Not all of them fit, most are too wide for a typical 25-26" cabinet that 6cf RV fridge is sitting in. When you'll find one that fits, don't expect much bargain, could be $500 or more, for 9cf-11cf model. Again, if you're not DIY, you have to pay somebody to remove the dead propane fridge and install 120V fridge. Fridge of that size could draw more power than 200W solar could provide, you'll need either +500W solar or a generator. Unless you always camp with grid power. Getting from home to the camp, it will more-less stay cool until you open the door.
Cheap small dorm/undercounter fridge from Walmart with volume less than 6cf could easily draw more energy than a modern energy-efficient $600 fridge with 11cf volume.
I would consider fixing your propane fridge first. They are not perfect, but they don't need solar or generator and last many years. Your RV is used, a new/fixed propane fridge could outlast the rig, no worries.